Niche construction: evolutionary implications for parasites and hosts

• Organisms can determine their evolutionary trajectory by their choice of habitat or behaviour.
• This may guide the evolution of traits which underlie the interaction of parasites and hosts.
• Genotype–environment covariance may be an important driver of these evolutionary changes.

Organisms can determine the environment they experience through the process of niche construction. This may have important evolutionary consequences by exposing them to new selection pressures, producing a faster response to selection, and building suites of coadapted traits. Traits of the parasite which influence the likelihood of encountering different host environments, or which change the host environment, can be regarded as niche construction traits, as can traits of the host which influence the likelihood of the host being infected by parasites. A niche construction perspective may provide new insights into the evolution of host/parasite interactions; this is illustrated with several examples from the viewpoint of both parasite and host traits.